Bike helmet critics using their heads

The latest claims by Jake Olivier et al again obfuscate the facts about Australia's mandatory bicycle helmet laws.

To obfuscate is:

1. to make so confused or opaque as to be difficult to perceive or understand
2. to obscure or darken
3. to perplex or bewilder

Obfuscation is remarkably simple when dealing with media who assume the accuracy of what you say and fail to research other facts that negate the claims being made.

A good example of obfuscation is combining the issues of cycling infrastructure and helmet laws, the inference being that helmet law critics are opposed to cycling infrastructure. Helmet law critics have always advocated better cycling infrastructure. If they weren't discouraged by a penalty, they'd prefer to cycle on a pathway than drive their cars.

Obfuscation can also be demonstrated by considering the points made by Olivier et al in the National Times article:

"Those opposed to the helmet law cite personal liberty issues or say helmets aren't worth the bother. Both arguments are weak and easy to counter."

No they don't and no they aren't. Those opposed to helmet laws realised 20 years ago that it's pointless arguing the worth of personal liberty with people who don't understand the concept. Critics have been arguing for 15 years that the hospital injury and cycling participation results prove that helmet laws are detrimental to public health and safety.

"First, cycling has flourished since the helmet legislation was enacted in 1991. There is no sign of widespread grassroots ideological opposition to the law, any more than there is to mandatory helmets for motorcyclists or seatbelts in cars. Cycling rates are rising rapidly and claims that repealing the law will encourage more cyclists are light on fact and heavy on opinion."

Olivier et al ignore all surveys showing that public cycling participation declined by 30-40% immediately the laws were enforced in different states.

The same result was experienced in New Zealand when helmet laws were enforced and the failure of the Melbourne and Brisbane bike share schemes is blamed across the globe on Australia's helmet laws.

Surveys show Australia's level of cycling participation didn't recover to pre-law numbers until about the year 2000, differing in each state, by which time police enforcement had eased and, as has been apparent for years, huge numbers of people risked prosecution by cycling the convenient and comfortable way that they prefer - without a helmet.

In his article published by The Conversation website on June 23, 2011, Olivier concedes that the number of child cyclists reduced by around one third following helmet law enforcement, although he cites one study commissioned by the Road Traffic Authority but ignores the detail.

For example, a 1993 study conducted by Smith MC and Milthorpe MW (An observational survey of law compliance and helmet wearing by cyclists in New South Wales, RTA 1993 (ISBN0-7305-9110-7) found:

• school students riding to/from NSW schools: total counts 3107 in 1991 to 1648 in 1993, a drop of 47%
• for female students the figures were 654 in 1991 down to 222 in 1993, a drop of 64%
• for secondary female students the reduction in cycling was greater: 455 in 1991 to 106 in 1993, a drop of 77%
• for secondary children cycling to school in Sydney the reduction was from 904 to 294, a drop of 67%.
• the largest reduction in cycling was among secondary female students in Sydney: 214 in 1991 down to 20 in 1993, a drop of 90.6%

Between 1991 and 1993, the NSW Road Traffic Authority measured a decrease in <16 child cycling of 44% (Walker M, Law compliance among cyclists in New South Wales, April 1992 / A third survey: Road and Traffic Authority Network Efficiency Strategy Branch, July 1992 / Smith N, Milthorpe F, An observational survey of law compliance and helmet wearing by bicyclists in New South Wales - 1993: Roads and Traffic Authority, 1993).

Whether it's a third, 44% or 90.6% reduction in child cycling, it could reasonably be expected that such declines would see a roughly commensurate reduction in accidents/injuries among children after helmet law introduction, regardless of whether or not they wore helmets.

As presented in the Voukelatos/Rissel study, The effects of bicycle helmet legislation on cycling-related injury: The ratio of head to arm injuries over time, injury trends for children in NSW were:

Table 2. Cases of head and arm injuries for hospitalised cycling-related injuries by age group

Head injuries came down: comparing the first three years of data (88-91 av 400) to the following three years (91-93 av 305), a reduction of 24%; or comparing the first four years of data (88-92 av 373) to the following four years (92-96 av 317), a reduction of 15%.

Arm injuries went up: comparing the first three years of data (88-91 av 360) to the following three years (91-93 av 440), an increase of 22%; or comparing the first four years of data (88-92 av 370) to the following four years (92-96 av 515), an increase of 39%.

Olivier et al have conceded that child cycling fell by about 33% when the helmet law was introduced (with children helmet wearing rates increasing from about 20% to more than 60% within two months of helmet law introduction), yet head injuries only declined by 24% on a three year comparison and just 15% on a four year comparison.

Trends in Australian children traveling to school 1971-2003: burning petrol or carbohydrates? (final page Appendix 4) shows the decline in walking and cycling to school by children across Australia aged 5-9 and 10-14 from 1971 to 2003 (other = cycling). This and other surveys suggest the downturn was permanent.

Olivier et al maintain that there was an increase in adult riders after the helmet law was introduced, citing Walker, Cameron, Smith and Milthorpe (see below).

Above is an extract from Cycling Down Under: A Comparative Analysis of Bicycling Trends and Policies in Sydney and Melbourne by John Pucher, Jan Garrard and Stephen Greaves (Journal of Transport Geography, Vol. 18, 2010). Based on population (1986 - 0.7% x 3,472,000 population = 24,304 / 2006 - 0.7% x 4,282,000 population = 29,974) this suggests about 5,670 more Sydney cyclists riding to work in 2006 compared to 1986.

Above is an extract from Travel to work in Australian capital cities, 1976-2006: an analysis of census data by Mees, Sorupia and Stone (GAMUT and University of Melbourne, December 2007) showing Sydney adult cycling to work fell from 9,262 in 1986 to 8,934 in 1991 to 8,193 in 1996 to 9,223 in 2001.

The 2008/09 Sydney Household Travel Survey (p26) shows there were 106,000 bike trips on average weekdays in 2008/09, compared to 101,000 bike trips in 2001/02 (see below), and data from Cycling in New South Wales: What the data tells us shows Sydney had Australia's lowest proportion of bicycle use for journeys to work at 0.7% in 2006 (see below).

Above is an extract from Cycling in New South Wales: What the data tells us prepared for the Premier's Council for Active Living, December 2008

"Cycling rates are rising rapidly"?

All mainstream media and web polls on the helmet law issue have had large public responses, with all showing 50-60% support repeal of the law.

Research published in 2012 shows that, based on national surveys in 1985/86 and 2011, Australia's rate of per capita cycling participation in Australia was 22.3% below the rate of population rate. Comparing populations aged 9+, there is 37.5% less cycling per capita than four years before the helmet law.

Cycling rates have been increasing from a low base thanks mostly to bare-head participation but still lag well behind 1985/86 per capita participation levels. Just because hundreds of thousands of discouraged Australian cyclists have been ignored by the media, the parliament and the medical establishment for 20 years doesn't mean that grassroots opposition isn't there.

Olivier et al can keep ignoring the facts surrounding cycling participation in Australia, but it will keep rendering their arguments false.

"Second, there is solid evidence that cyclist head injuries have declined while other cyclist injuries have not during this period: that is, when accidents happen, helmets make an important difference. No one should need reminding that serious head injuries may exact a lifelong toll on the individual and be a great cost to the community."

There is solid evidence of a decline in the proportion of head injuries but an increase in the overall number of cyclist injuries following helmet law enforcement, resulting in about 30% more hospital admissions per cyclist numbers surveyed on the road.

The head and all body injuries argument only works if you obfuscate the facts by ignoring the overwhelming evidence that cyclist numbers declined and participation rates remain less than pre law and low compared to the global average.

"It is worth examining this finding in a little more detail because it lays bare why opponents of bicycle infrastructure are on the wrong track. Our research published last year established that bicycle-related head injuries fell by 29 per cent immediately following mandatory helmet legislation. That reduction was unrelated to any other changes occurring in cycling around that time: helmets plainly worked as intended."

A more detailed examination of cycling infrastructure opposition involves nothing but a reference to helmet laws? It's fortunate these issues aren't being confused.

When the helmet laws were introduced in different states from 1990 to 1992, cycling participation fell by about 30% in each case. According to Olivier et al, head injuries fell by 29%. Overall hospital admissions didn't change. Think about it.

"We then singled out head and arm injuries for comparison, to see whether helmets were doing their job. Arm injury rates reflect what is happening in the cycling environment, such as general safety improvements and the behaviour of cyclists. If more riders take to the roads, for example, or ride longer distances, more accidents resulting in arm injuries will follow. Helmets only protect heads, so comparing arm and head injury rates gives a clearer picture of the effect of helmet-wearing. We found that arm injuries have indeed mirrored the large growth in cycling numbers in NSW and Australia in general. In the past decade in particular, imports of bicycles and cycling participation rates have grown and the average daily number of cyclists in the Sydney CBD has trebled. Before the helmet law, the head-injury rate was consistently higher than that for arm injuries. But after the helmet law, head injuries dropped below arm injuries and the two gradually diverged. Arm injury numbers rose steadily at a rate of 3.3 per cent a year (as cycling rates grew), yet head injuries stayed relatively flat. By 2006, the head injury rate had fallen to almost half that of arm injuries. The numbers tell this good-news story: between 1991 and 2010, the NSW population increased by 22 per cent. In that time, arm injuries rose by 145 per cent, yet head injuries rose by just 20 per cent (and in the past decade alone, cycling participants increased by 51 per cent). Put another way, if head injuries had increased at the same rate as arm injuries, we would have expected 1,446 head injuries in 2010. Instead, there were only 706 – that's a lot of serious harm avoided in just one year."

In their Accident Analysis and Prevention paper, Olivier et al use the following graph to illustrate their point that head injuries did not increase at the same rate as arm injuries:

The graph ratios are based on injuries per 100,000. Although not precise, below are estimated annual arm injuries based on the ratios charted above compared to annual population:

June 1991 - 5,898,731 / 58.9 x 12 = 707
June 1992 - 5,962,569 / 59.6 x 13 = 775
June 1993 - 6,004,880 / 60 x 14 = 840
June 1994 - 6,060,190 / 60.6 x 14 = 848
June 1995 - 6,126,981 / 61.3 x 15 = 920
June 1996 - 6,204,728 / 62 x 17 = 1,054
June 1997 - 6,276,961 / 62.8 x 16 = 1,005
June 1998 - 6,339,071 / 63.4 x 17 = 1078
June 1999 - 6,411,370 / 64.1 x 16 = 1,026
June 2000 - 6,486,213 / 64.9 x 20 = 1,298
June 2001 - 6,575,217 / 65.8 x 17 = 1,119
June 2002 - 6,628,951 / 66.3 x 18 = 1,193
June 2003 - 6,672,577 / 66.7 x 20 = 1,334
June 2004 - 6,707,189 / 67 x 21 = 1,407
June 2005 - 6,756,457 / 67.6 x 23 = 1,555
June 2006 - 6,816,087 / 68.2 x 23 = 1,569
June 2007 - 6,904,942 / 69 x 22 = 1,518
June 2008 - 7,014,887 / 70.1 x 22 = 1,542
June 2009 - 7,133,398 / 71.3 x 21 = 1,497
June 2010 - 7,238,819 / 72.4 x 21 = 1,520

A similar estimate can be made for head injuries based on the ratio per 100,000 population charted above:

June 1991 - 5,898,731 / 59 x 10 = 590
June 1992 - 5,962,569 / 59.6 x 11 = 656
June 1993 - 6,004,880 / 60 x 11 = 660
June 1994 - 6,060,190 / 60.6 x 11 = 667
June 1995 - 6,126,981 / 61.3 x 11 = 674
June 1996 - 6,204,728 / 62 x 12 = 744
June 1997 - 6,276,961 / 62.8 x 12 = 754
June 1998 - 6,339,071 / 63.4 x 12 = 761
June 1999 - 6,411,370 / 64.1 x 12 = 769
June 2000 - 6,486,213 / 64.8 x 13 = 842
June 2001 - 6,575,217 / 65.8 x 11 = 724
June 2002 - 6,628,951 / 66.3 x 12 = 796
June 2003 - 6,672,577 / 66.7 x 12 = 800
June 2004 - 6,707,189 / 67 x 13 = 871
June 2005 - 6,756,457 / 67.6 x 12 = 811
June 2006 - 6,816,087 / 68.2 x 14 = 955
June 2007 - 6,904,942 / 69 x 13 = 897
June 2008 - 7,014,887 / 70.1 x 12 = 841
June 2009 - 7,133,398 / 71.3 x 11 = 784
June 2010 - 7,238,819 / 72.4 x 10 = 724

The injury decline after 2006 is attributed by Olivier et al to cycling infrastructure improvements, although it is unlikely that construction of infrastructure in some NSW locations would have an immediate impact on statewide injury tolls.

A likely explanation for the plateau in arm injuries and decline in head injuries since 2006 is reduced police enforcement and the increasing numbers of cyclists without helmets, resulting in safety in numbers and less risky riding by unhelmeted cyclists. Olivier et al note that there has been no official helmet wearing survey in NSW since 1992 but most people agree anecdotally that far more people nowadays cycle without a helmet.

If injury numbers after 2006 are biased by other elements such as improved infrastructure and/or less helmet wearing, arm injuries increased 121.9% from 707 in 1991 to 1,569 in 2006. Head injuries increased 62% from 590 in 1991 to 955 in 2006.

From 1991 to 1998, arm injuries averaged 903 per year and from 1999 to 2006 they averaged 1,313 per year - a 45.4% increase. From 1991 to 1998, head injuries averaged 688 per year and from 1999 to 2006 they averaged 821 per year - a 19.3% increase.

Olivier et al do not accept there was a significant or prolonged downturn in NSW cycling participation, contrary to the references above, but Mees et al calculate Sydney commuter cycling at 8,934 in 1991 and 10,886 in 2006 - a 21.8% increase.

The June 1991 population estimate was six months after adult helmet laws were introduced in NSW and this reduced the number of cyclists surveyed. Mees et al calculate Sydney commuter cycling at 9,262 in 1986 and 10,886 in 2006 - a 17.5% increase.

Sydney's commuter cycling numbers were likely to have been significantly higher in 1990 before the helmet law, based on earlier trends. The NSW population increased 15.6% from 1991 to 2006 and 23.2% from 1986 to 2006.

Data from the Health Department in Western Australia is useful if comparing head and arm injury rates among cyclists pre and post law.

The two charts below show the shift in body injury distribution from 1988 to 1998 in WA, according to Bicycle Crashes and Injuries in Western Australia, 1987-2000 - Road Safety report RR131.

WA cyclist hospital admissions

1985 - 623
1986 - 660
1987 - 630
1988 - 698
1989 - 596
1990 - 638
1991 - 730
1992 - 574
1993 - 633
1994 - 644
1995 - 660
1996 - 715
1997 - 754
1998 - 850
1999 - 862
2000 - 913

Upper extremity (arm) injuries increased sharply, despite a 30%+ reduction in cycling that recovered to pre-law numbers by the year 2000. Head injury numbers were also at about the same level by then.

So with similar public cycling numbers by 2000, there were about 50% more hospital admissions than pre-law because of an increased number and proportion of non-head injuries.

As in NSW, head injuries didn't go down. Arm injuries went up. Olivier et al only attribute increased arm injuries to increased cyclist numbers and dismiss any other cause, including more arm injuries per cyclist on the road. More arms injuries were/are due to increased risk compensation by helmeted cyclists resulting in more crashes per cyclist, with evidence suggesting higher speeds and crash responses may also cause more arm injuries.

The NSW population increased by 34% from 1986 to 2011 (5,401,881 to 7,238,819). The number of people in NSW cycling per day increased by 9.8% from 1985/86 to 2011.

Olivier et al have previously claimed that there was not a similar reduction in head injury rates among pedestrians and this reflects helmet prevention of cyclist head injury. A more accurate comparison might be made with NSW pedestrian death and injury tolls which reflect reduced speed limits, tougher drink driving laws, improved road safety and falling injury rates for other road users:

NSW pedestrian fatalities and injuries

Source : RTA document Road Traffic Crashes in New South Wales 2007

Since bicycle helmet laws were introduced, pedestrian injuries have almost halved, indicative of general road safety improvements - yet cyclist injuries have increased.

Olivier et al extrapolate their inaccurate point with the headline claim that mandatory helmets thus prevented 740 head injuries in NSW in 2010. The evidence suggests they more likely caused several thousand broken arms and sprained wrists.

"Importantly, from 2006 onwards, we detected a second, even more heartening change in the trend – instead of cycling injuries continuing to increase, they actually began to fall, particularly head injuries. This change is unlikely to be related to helmet legislation alone. Indeed, the timing corresponds closely with more money being spent on cycling infrastructure, notably cycleways. On a per population basis, 2010 enjoyed the lowest head-injury rate since the collection of hospitalisation data going back to 1988-89."

Indeed, cyclist injury rates in WA stabilised from the year 2000 (roughly 50% above their pre-law level) and, as above, this was about when bare-head cyclists started to reappear in the streets. There have been no official cyclist helmet wearing surveys in Australia since 1994, a missing data element that allows falling injury rates to be attributed to helmets.

Olivier et al continue to base their injury arguments on a per population basis instead of a per cyclist basis, with the NSW population increasing 22% and NSW cycling increasing by less than half that rate.

"Bicycles are inherently unstable and cyclists will still crash on cycleways and in other off-road environments. In any cycling crash, wearing a helmet properly protects the most important part of the body. However, helmets alone should never be seen as a panacea. They are one important component in the overall cycling safety environment. Intuitively, we all know that segregating cyclists from cars, trucks and buses through cycling infrastructure makes collisions less likely. There's no doubt now that greater spending on cycling infrastructure and mandatory helmets have jointly delivered major benefits on two fronts – fewer cycling injuries, particularly head injuries, and more people enjoying the health benefits of safe cycling. Surely it would be irresponsible to do anything but continue down the path of making cycling safer. Keeping helmets and building more cycleways is unquestionably the way to go."

Australian politicians have had a half-hearted approach to cycling infrastructure funding for the past 20 years because mandatory helmets protect cyclists from serious injury so there's nothing much to worry about. According to the academic experts, helmets have slashed serious injuries.

Statistical and anecdotal evidence shows that large numbers of people remain discouraged from cycling either frequently or at all, and their alternative car transport endangers the safety of all road users while reducing demand for improved cycling infrastructure.

Study faults

In their AA&P paper, OIivier et al state in the introduction that "when considering the biomechanical helmet padding system protecting the head, Newtonian laws of physics dictate that an impact force via the helmet to the head during a reasonable velocity crash (50–60 km/h or less) must reduce the magnitude of the blunt force imposed onto the rider’s head, and thus the severity of the head injury.

Bicycle helmets are only tested to a drop speed of 20kmh and there is general consensus that compression and collapse of the foam and casing mean there is little head or brain injury protection above this speed.

The paper bases its estimate of cyclist number improvements on Australian bicycle import figures since 2000, as well as government road surveys and the Exercise, Recreation and Sport Survey, to illustrate that cycling has been increasing since that year.

Increasing cyclist numbers since 2000 have never been in dispute but the study ignores cyclist surveys showing little to no growth during the 1990s following helmet law enforcement. For example, Mees et al document Sydney commuter cyclist numbers at 9,262 in 1986 and 9,223 in 2001.

Olivier et al will not accept the helmet law influence on Melbourne/Brisbane bike share projects, they will not accept the majority opinion polls against helmet laws, they will not accept that the many cyclists nowadays without helmets are willing to risk prosecution, and as a result they will not accept that if helmet laws were repealed they would achieve their desired increase in cycling participation.

Their claim that cyclist head injuries would double does not correlate with any of the hospital evidence at the time of helmet law enforcement or since.

Sourced from OECD International Transport Forum Road Safety Annual Report 2011, it is worthwhile comparing Australia's cyclist fatality rate since its first helmet law enforcement in 1990 with the 28 member countries of the international forum. Two of the countries (Australia and New Zealand) have all age bicycle helmet laws and altogether 10 have child helmet laws.

Australia (all age helmets)

Cyclist fatality decrease 1990-2010 = -53%
Motorcyclist fatality decrease 1990-2010 = -15%
Car occupant fatality decrease 1990-2010 = -41%
Pedestrian fatality decrease 1990-2010 = -60%

All countries averaged

Cyclist fatality decrease 1990-2010 = -53%
Motorcyclist fatality decrease 1990-2010 = -21.8%
Car occupant fatality decrease 1990-2010 = -50.2%
Pedestrian fatality decrease 1990-2010 = -59%

Countries with any helmet law

Cyclist fatality decrease 1990-2010 = -49.5%
Motorcyclist fatality decrease 1990-2010 = -12.9%
Car occupant fatality decrease 1990-2010 = -50%
Pedestrian fatality decrease 1990-2010 = -56%

Countries without any helmet law

Cyclist fatality decrease 1990-2010 = -54.9%
Motorcyclist fatality decrease 1990-2010 = -27%
Car occupant fatality decrease 1990-2010 = -50.3%
Pedestrian fatality decrease 1990-2010 = -60.7%

The OECD's International Transport Forum Working Group on Cycling Safety this year issued a preliminary recommendation:

Helmet usage reduces the severity of head injuries cycle crashes but may lead to compensating behaviour that otherwise erodes safety gains.

• reduced injury risk (due to increased helmet usage)
• increased crash risk (due to an often claimed change in behaviour amongst cyclists who take up wearing helmet)
• less cycling (leading to a reduced number of accidents and injuries, but also to a higher accident risk for those who still bike)

As a forum member, Australia presumably endorses this recommendation. It's little wonder that after 20 years, no country other than New Zealand has followed Australia's example of national all age bicycle helmet laws, apart from Israel which repealed its adult helmet law in 2011 based on evidence from Australia, New Zealand and its own four year discouragement of cycling.

This latest paper by Olivier et al can be accepted and portrayed by the media as a rebuttal of the evidence behind the call by Freestyle Cyclists for helmet law repeal.

Alternatively, the media can research evidence showing the bicycle helmet law is a public health and safety disaster that is increasingly opposed in other countries not wanting to emulate Australia's obesity crisis or upset their more successful reductions in cyclist fatalities and injuries.